Submitted to: Biocontrol
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/2013
Publication Date: 12/1/2013
Citation: Porter, S.D., Kumar, V., Calcaterra, L.A., Briano, J.A., Seal, D.R. 2013. Release and establishment of the little decapitating fly Pseudacteon cultellatus on imported fire ants in Florida. Biocontrol. 96(4): 1567-1573. Interpretive Summary: Red imported fire ants are a major economic and urban pest throughout the southeastern United States and parts of California. The little decapitating fly Pseudacteon cultellatus from Argentina was released in Florida as a self-sustaining biological control agent against the red imported fire ant, Solenopsis invicta by a USDA-ARS scientist at the Center for Medical, Agricultural and Veterinary Entomology in Gainesville, FL working in cooperation with colleagues from the University of Florida's Tropical Research and Education Center in Homestead, FL and the Fundación para el Estudio de Especies Invasivas in Hurlingham, Argentina. This small parasitic fly was expected to do especially well in parasitizing small fire ant workers associated with multiple-queen colonies. Two and a half years after being released in the field, this fly appears to be established at a site in Gainesville, FL and a second site near Miami, FL. Fly populations at both sites have remained very low (= 1% of total Pseudacteon flies). Flies have expanded 500 m away from the first site, but expansion has yet to be detected at the other successful release site. Because P. cultellatus populations remain very low, impacts on imported fire ants are likely to be minimal. Further releases of this fly in the United States should be limited to a few additional sites in different habitats or climatic regions where this it might be more successful.
Technical Abstract: The little decapitating fly Pseudacteon cultellatus from Argentina was released as a self-sustaining biological control agent against the red imported fire ant, Solenopsis invicta, in Florida to parasitize small fire ant workers associated with multiple-queen colonies. This fly appears to be established at two of five release sites, but populations still remain very low (=1% of total Pseudacteon flies) and localized more than two years after their release. The proportions of Pseudacteon flies trapped during monitoring were 91% P. curvatus and 8% P. obtusus in the Gainesville area (North Florida) compared to about 80% P. curvatus and 20% P. tricuspis at the release site near Miami (South Florida) where P. obtusus is not yet established. The formerly abundant P. tricuspis continues to persist in the Gainesville area, but at very low levels like P. cultellatus. Further releases of P. cultellatus in the United States should be limited to a few additional sites in different habitats or climatic regions where this fly might be more successful.